Control of reversing apparatus for heating furnaces



. 3 Sheets-Sheet l June 2, 1925.

G. H. 'I sLEY CONTROL REVERSING APPARATUS FOR HEATING FURNACES FiledJune 25, 1921 cs. H. lsLEY CONTROL 0F REVERSING` APPARATUS F'OR HEATINGFURNACES June 2,1925. 1,540,076`

Filed June 25, 1921 3 Sheets-Sheet 2 June 2, 1925- 1,540,076

- G.'.H. 'ISLEY Y CONTROL OF REVERSING PPARATUS FOR HEATING FUIRNACESFiled June 25, 1921 3 Sheets-Sheet 3 Patented June 2, 1925.

UNITED STATES k1,540,076 PATENT OFFICE.

GEORGE H. ISLEY, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO MORGAN CON-STRUCTION COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORATION OFMASSACHUSETTS.

CONTROL OF REVERSING APPARATUS FOR HEATING FURNACES.

Application filed June 25, 1921.

To U 't0/10m.n may camcom:

Be vit known that l, GEORGE H. IsLnY, a citizen of the United States,residing at lllorcester, in the county of W'orcester and(flomn'ionwealth of Massachusetts, have invented a new and usefulImprovement in the Control of Reversing Apparatus for Heating Furnaces,of which the following, together with the accompanying drawings, is aspecification.

The present invention relates to improvements in the control yofapparatus which is used with the regenerative type of furnace forreversing the course of the burning gaseous fuel through such a furnace.

The present invention relates particularly tov the control of thereversing apparatus forming the subject matter of my copendingapplication Serial No. 268,391, filed Decen'i bei' 26, 1918. rlhepresent invention contemplates various novel and improved featureswhereby the control of the operation of a reversing apparatus of theabove de scribed type .is rendered particularly simple and eli'cctive,and whereby the efficiency and reliability in operation of a furnaceequipped with reversing apparatus of this type isy greatly increased.These and other :ulvantageous features offmy invention will hercinaf ,ermorefully appear in the following description, reference being had tothe accompanyingl drawings, wherein- Fig. l is a diagrammatic Viewillustrating the application of my improved revers ing apparatus to aregenerative furnace of a well known type.

Fig. 2 is a diagrammatic view similar to Fig. l, showing the parts of myimproved reversing apparatus, in a different position.

Fig. 3 is a plan view of one of the revers- .ing units to which myimproved control is applied.

Fig. s'lis a side view of the apparatus shown in Fig. l. certain partsbeing broken away to disclose more clearly the construction thereof.

Fig. 5 is a longitudinal sectional view on the line '135 of Fig. 3. n

Fig. G is a plan view of a cont-rol device emploved in connection withone of the reversing units.

Fig. T is a view in side elevation of the control device shown in Fig.G.

Fig. S a diagram ofa portion of the Serial No. 430,431.

wiring for two reversing units and showing in perspective the angularrelation between the control wheels of two duplicate reverfing umts. l

F ig. S) is diagrammatic view showing the position of the reversing unitwith which is associated one of the control wheels shown in Fig. 8.

l0 is a diagrammatic view of the reversing unit with whiclris associatedthe other control wheel shown in Fig. 8.

Like reference characters refer to like parts in the diil'lierentfigures.

Referring lirst to the diagran'i of Fig. l, which illustrates theapplication of my in-I vention to a heating furnace, the furnace l, ofany well known type, is provided at its opposite ends with gasregenerator passages 2, 2 and adjacent air regenerator passages 3, 3',arranged in the manner common to furnaces of this general type. In theuse of duplicate reversing` instruinentalities for such a furnace, asdisclosed in my above mentioned copending patent application, livecoterrninousflues are arranged at each end of the furnace adjacent therespective regenerators, and hood structures 4 and l are disposed inoperative relation to thi` respective sets of llne terminals. In eachset of terminals, the gas regenerator passages i2, 2 of the furnaceconnect with gas regenerator flues ,5, 5. and the airk regeneratorpassages 3, 8 connect with air regenerator fines 6, 6. Separate pairs ofstack fines 7, '.7 and 7', 7 are arranged between the air and gasregeneratl'ir tlues 5, 6 and 5, 6', the stack fines being connected to acommon stack passage 8. Gas supply flue terminals 9, 9 are also arrangedin alinement with the regenerator flue terminals above described.

The duplicate reversing instrumentalities are of the construction shownin Figs. S. al. and 5, and consists essentially of a pair of hoodstructures referred to generally as le and 4 in Fig. l, the hoods ofeach structure being movable in unison and each adapted to bridge overtwo adjacent flue terminals of its associated set. ln either positionofthe hood structures, as illustrated in Figs. l.

`and one air fine 6 or 6 and one gas flue.

9 or 9 is always left unbridged, as the case may be. It will be wellunderstood that under these cenditiens with the hood strncllll lofi

tures 4 and 4f in the positions shown in Fig. 1, the passage of air andgas through the furnace 1 is from right to left. whereas when the hoodstructures 4 and 4f are moved to their other positions, as shown in Fig.2, the direction of the products of combustion through the furnace isreversed, as indicated by the arrow.

Referring now to Fig. 5, a water seal casting 10 is so formed as toprovide the several alined flue terminals G, 7, T, 5 and 9 whichregister with the corresponding passages provided in the brick work 11,the two terminals 7, 7 opening from a single passage 8 which leads tothe stack. The casting 10 also provides a surrounding rim or flange 12,which is adapted to maintain a sufficient depth of water for sealingpurposes around and between all of the flue terminals, as will bereadily understood. On opposite sides and near each end of the asting1() are pro vided bearing lugs 13, 13, upon which are pivotally mountedalined pairs of bell cranks 1-1, one crank being provided near each endof the four corners of the casting 10. As best shown 1n Fig. #1, thelranks at one end of the casting 10 are oppositely dis* posed from thoseat the other end of the casting, so that in the position shown, thecranks 14 at the left hand end have their shorter arms directeddownwardly, while the cranks 14 at the right hand end have their shorterarms directed upwardly. The long arms of the bell cranks 1-1 areutilized for the movement of a hood supporting frame 15, which issubstantiallyv rectangular in shape, and to which is secured a pair ofhoods 1G and 1T. rThe hoods 16 and 1? meet at substantially the centerof the frame 15 and are provided with downwardly extending flanges 18that are adapted to dip beneath the water in the casting 19, for thepurpose of providing a seal, as hereinafter described.

The frame 15 provides at each corner a lug 19, by means of which thelong arms of the bell cranks 1e may be connected thereto through shafts29 extending across the frame 15 through the lugs 19 and connected attheir ends to the cranks 1e. The lon-g arms of the cranks 14,- areparallel and thus provision is made for imparting to the frame 15 andhoods 1G and 1.7 a parallel motion with respect to the axes of rotationof the cranks 11. Links 21 are connected to the short arms of the cranks11 on each side of the frame 15` each pair of links 21 extending towardeachother and being inelosed in a tubular casing Each link 21 issurrounded bhv a spring 23, which is confined at its ends between a head2J: closing one end of the casing 22 and a collai 25 carried by the link21, the collar being adapted to slide within the casing 22.

In the position of the parts shown in lfig.

si, with the frame 15 and the two hoods 16 and 1T in their extreme righthand positions, the springs 23, two on each side of the appa ratus, areunder extreme compression and are therefore tending to rock the bellcranks 1% in a couiiterclockwise direction through the collars 25 andlinks 21. Owing to the 'forces thus exerted by the springs 23, the actof moving the frame 15 and the hoods 16 and 1T to the left about thecenters of the cranks 11 requires only a relatively lsmall force incomparison to that which would otherwise be required to effect thecombined translatory and lifting movements of the parts. parts, wherebythe above described result is obtained, forms no part of the presentinvention, and is fully disclosed in my above mentioned copending patentapplication, no further discussion thereof is deemed necessary herein.

The power required for rocking the cranks 11 in the manner abovedescribed is obtaiuet from an electric motor 26 on a pedestal 2i'provided at one end of the casting 1t). The shaft of the motor 26 isprovided with a pinion 28, which is in mesh with a gear 29 mounted atone end of a conntershaft Bt), the wears being inclosed within a casing31. The shaft 30 is journalled in a housing 32 e tending upwardly fromthe pedestal 2.7, and is provided with a worin in mesh with a worm wheel3st. The worm wheel 3st carried on a transverse shaft which projects atits ends beyond the housing 32, and upon t which is mounted a pair ofcranks E16. The cranks 35 are connected by rods 3T to the right handcross shaft 20, to which the long arms of the adjacent cranks 1% arealso attached. lt is obvious that rotation of the motor shaft will betransmitted to the shaft 35 through the gearing above described, andthat a half revolution of the shaft $15 is adapted to effectone completeoperation of the hood structure. That is to say, as the cranks 36 movethrough the lower half of their travel, the hood structure is carriedover to the left, from the position shown in Fig. 5. while when thecranks 36 move through the upper half of their travel. the hoodstructure will be moved from its e1:- treme left hand position back tothe position illustrated in Fig. rlhe position which the hood structureoccupies when in its extreme left hand position is illustrateddiagraminatically in Fig. 2.

Each flue terminal 9. 9 is equipped with a swinging cover 38, which isadapted to move on a trunnion shaft supported on the bottom of thecasting 10. The cover 3S formed with a project-inglug` 40 whirli isadapted to be engaged by the flange. portion 18 running along thebottoni of the outside hood 1T of each pair. ln the position of theparts illustrated in Fig. 5, that portion ris this particulararrangement et' i:

lll)

Ml of the flange 18 bea-ring on thellug 40 holds the cover 38 in raisedposition and thus permits the flow of gas from the flue terminal 9 tothe fiue terminal 5, which'latter is connected to the gas regeneratorpassage 2 of the furnace, as indicated in Fig- 1. The movement of thehood structure to its ,left hand position as described above, for thepurpose of reversing the furirace, disengages the (lange 18 from the lug4() and allows the cover 38 to descend by gravity so as to cover andeifectually seal the gas terminal 9. The arrangement of the parts issuch that the cover 38 moves its full. distance downwardly and seals theterminal 9 before the flange 1S is entirely lifted out of the water inthe casting 10. In this way the escape of any gas past the flue terminal9 during the operation of reversing is effeetually prevented7 since thecover 38 descends fully and makes a. water seal around the flue terminalbefore the water seal made bv the `flange 18 is broken.

lVilh the hood mechanism in the position shown in Fig. 5, the frame 15is so disposed as to maintain a damper or cover 4l in operative relationto the air regenerator fiue terminal G. This cover 41 is pivotallymounted on the left hand end of the hood 1,6, as indicated at 42, andthe position of the damper 41 may be controlled manually or otherwise bya chain or other suitable connection 43, so as to vregulate the amountof air which enters the' furnace ythrough the fine 6. When the hoodstructure moves to the left, as described above, in the act of reversingthe furnace and thereby connecting the flue terminal G with the adjacentflue terminal 7, the cover 41 will be raised about its pivot 42 andsimultaneously carried to an inoperative position beyond the terminalsof all the lues. as illustrated diagran'imatically in Fig. 10.

It will be understood thatl the reversing instrumentalities abovedescribed are identical in all respects. and that bv their ar-.'angement as described in my' above men# tioned eopending application,such instrumentalities are sufficient to takecare of the completereversal of a regenerative furnace. Each hood structure functions withrespect to'both gas and air, so that any necessity for separate andindependent air and `gas valves is eliminated. One of the greatadvantages to be gained by the use of the reversing` instrumentalitiesabove described. lies in the fact that such instrumentalities may beplaced in close proximitypto the air and gas regenerator passages of thefurnace, which results in greatly reducing' the lengths of theunderground flue passages,y with a consequent reduction in the wastageof gas when the furnace is reversed. Obviously, the operation of thereversing instrumentalities can be controlled in any desired way. but

in order to permit the convenient control ot the operation at a pointremoved from the furnace, I propose to provide improved electricalcontrol apparatus, whereby the move ments of both hood structures willat all times be under the control of the operator, and whereby the mostdesirable relation bctween the movements of the separate hood structuresmay be automatically obtained to reduce the wastage of gas to a minimum.

Referring now to Figs. 6 and 7 a control device is mounted within eachgear housingl 32 adjacent to one of the cranks 36. Each control devicecomprises a wheel 44 mounted on the shaft and carrying iieripherally agenerally cylindrical contact drum 45. The drum 45 is adapted tobe'engaged at times by a pair of contact fingers 46 and 47 that arecarried on an arm 4S. which is pivotally mounted on the shaft 35, for apurpose to be hereinafter described. Additional contact lingers 49, 50and 51 are also stationarily disposed in position to enga-ge otherportions of the drum 45.

As best shown in Fig. S, the contact drinn 45 is irregular in form andis so constructed that onlythe contact finger 49 remains in engagementtherewith during a complete revolution of the `wheel 44. The contactfinger 46 is adapted to engage only the projection 52 of the drum 45.while the contact linger 51 is adapted to only engage the projection 53.The contact finger 47 is in engagement with the drum 45 except when itregisters with the notches 54 and 55 thereof. while the contact finger50 is in engagement with the drinn except when it registers with thenotches 56 and 57. f The short notches 54 and 5G are diametricallyopposed with respect to the axis of rotation of the shaft and the sameholds true of the long notches and 57.

There is also illustrated in Fig. 8 the wiring of the panel forcontrolling the operation of the motor 2G. together with an arrangementof push buttons whereby the panel may be operated at a point removedtherefrom. It is obvious that the panel togcther with the apparatus forcontrolling the field strength of the motor 276 may be convenientlyplaced at some point near the motor 2G, whereas the several push buttonsmay beplaced at any Ldesired location on the oi'ierating iioor wherethey may be conveir iently reached by the operator. The elem tricalconnections between the control panel. the push buttons and the controldrum. previously referred to. will now be described.

The electric motor 26 comprises an armature 5S. a series field winding59. a shunt field winding GO and a commutating field winding 61. Thecontrol panel comprises a line switch 62. the stationary terminals 63and (i4 of which are connected to a suitable source of electricalenergy. the polarity of lll) the terminals being indicated. @ne of themovable poles 65 is connected to one termi-` nal ot' the series lieldwinding 59, the other terminal ot which is connected to one stationarycontact member GG of a contacter (i7. The corresponding movable contactmember Gt?, of the contacter (T is connected in series circuit relationwith the armature 5S and the commutating field winding (il et the motor2G. The winding- 6l is also connected to the other movable contactmember 69 of the contactor 6T. the corresponding stationary contactmember 70 being` connected to the other ino "able pole 7l ot' the switchG2.

One terminal of the closingl coil T2 ot the contacter' G? is connectedto the pole 65, and the other terminal thereof is connected to onestationary contact .73 ot' a push button having a bridging member T4.The other contact T5 ot' the push button is connected to the line switchterminal Tl through the contacts 76 and TT ot a. push button, in whichthe bridging member 'TS is normally in contact with the members T6 andT7. rl`he contact tingers 4J and 50h of the control device are alsoconnected to the line switch terminal Tl through the normally closedcontacts T6 and 'TT ot this push button. lVhen it is desired to startthe motor it. it is only necessary to depress the bridging member 'Tloit the upper push button. which completes the circuit ot the closingIcoil "T2 and causes the contactor (3T to close. This connects thearmature 58 ot the motor QG, across the terminals oft the line switch(l2 in series with the tield windings 5S) and (il. A lamp T9, locatedabove the push buttons and connectenV across the terminals ot thearmature 55h is then lighted and indicates to the operator that themotor 2G has started.

As soon as the motor starts, the shaft also starts to turn, whereuponthev contact lingers 4G and LT will immediately engage the contact drumlVhen this occurs, the circuit ot the closingcoil T2 is completedthrough the contact linger 47 and the contact linger 49, which is alwaysin engage meut with the drum l5 and is connected to one ot' two contactsSO which are automatically bridged by a member 8l upon the closing otthe contactor (i7. rllhe mot-or will then continue to operate, eventhough the bridging member Tl ol the upper push button be released bythe operator. due to the 'tact that the circuit ot the closing coil 72is maintained bv the engagement ot the contact with the drum before thecontact -i-T reaches the notch The continued operation ot the motor willthen cause the 'trame l5 and hoods 1G and l? to be lifted trom theposition shown in Fig. l. whereupon the cover 3S will close the 'tine Dbefore the raising ot the thinge portions 1B breaks the water seal. Themotor 2G will 1,54oio76 continue to operate until the shaft 35 hascompleted one halt ot a revolution. whereupon the contact linger 5()will register with the notch 5G and break the holding circuitl ot theclosing coil 72 of the contactor (3T. At this point in the revolution ofthe shait 35, the hoods 16 and l? will ha 'e reached their extreme letthand position, so that the air and gas regencrator tlues 5 and 6 will beconnected to the stach tlucs T` T, as indicated diagrammatically in Fig.Them or will then remain stationaryr until it is again started bydepressing the bridging` member Tel ol the upper push button, whereuponirst the contact and then the contact ai? will again engage the drum l5and complete the holding circuit ot the closing;i coil 72. The motorwill thus continue to operate to more the hood structure to the rightuntil the shat'tv has nearly completed another halt revolution; at thismoment thc contact 4T will reach the notch 54 and the motor will bestopped with the hood struc ture again in the position ot Fig. 5 withthe cover 3S open. The operation ot the motor 2G can be interrupted atany time, while the shaft 35 is turning through one haltl ot arevolution, by depressing the bridging` meinber 7S of the lower pushbutton. which interrupts the circuit between the closing coil T2 and theline switch terminal Tl.

if'leansare also provided for reversing the direction ot rotation ot themotor QG during the first part ot' a halt revolution of the shaft 35.The reversing means consists ot' a reversing switch S2, the contacts otwhich are so arranged as to reverse the direction of current flowthrough the armature 5S when the contacts ot' this switch are closed.One terminal of the closing coil 83 of the reversing switch S2 isconnected to the line switch terminal 65, andthe other terminal of thiscoil is connected to one stationary contact 84 of a. push button, thebridging:` member 85 of which is normally out of cngagement with thecontact S4. The other contact member 8G of this push button Visconnected to the contact linger 46 of the control device. The Contactfinger 4-6 is adapted to be engaged by .the drum 45 only when itsproject-ion 52 is in engagement with the linger 465 so that the circuitot' the closing coil S3 can only be completed during the first part ofthe upward movement ot the hoods 1G and 17 to the lett which results inlowering the cover 3S. In other words. it is only possible to reversethe direction ot rotation of the shaft 35 while Vthe iiange portions 18are still in .the water and the iiucs are sealed. The object ot this isto provide means whereby the amount of gas passing through the flue 9can be Varied by raising or lowering the hoods slightly and therebyeffecting the elevation of the cover 3S through its engagement by theflange 18. It is only possible for the operator to reverse the motorwhen the cont-act finger 46 is in engagement with the projection 52 ofthe drum 45.

As also shown in Fig..8, the contact finger 51 of the right hand controldevice is connected to the circuit of the control panel of the left handhood structure at a point between one terminal of the closing coil 72and the statymary lcontact 73 of the top push button. 'The contactfinger 51 is adapted to be engaged by the projection 53 of the drum 45just before the contact finger 5() registers with the notch 56 of thedrum 45 and thereby interrupts the energizing circuit of the coil 72, asreviously described.. In other words, just be ore the shaft complet-esone half of a revolution and then stops, kthe circuit of the closingcoil 72 of the other control panel is completed by the engagement of thecontact finger 51 with the projection 53, whereupon the motor of theother hood mechanism-starts to operate. Thekcontact finger 51 is inengagement with the projection 53 only long enough to allow the drum tostart to turn, whereupon the circuit of the closing coil 72 iscompleted, by the bridging of contact fingers 49 and 50 lby the drum 45.The motor of the left hand hood mechanism will be automatically stoppedas soon as the shaft 35 has completed onel half of la revolution, aswill be readily understood. Disconnecting switches 87 and 87 are,Lprovided between the fingers 51 and 51 and the coils 72 and 72,respectively, so that the motors may be operated independently of eachother.

From the foregoing it is apparent that Ihave provided means forcontrolling the operation of the duplicate hood structures of a furnace,whereby the position occupied by the hoods is at all. times under thecontrol of an operator who may beconveniently stationed at some desiredpoint on the operating floor remote from the hood actuating mechanism.Assuming that the hood structures occupy the positions diagrammaticallyillustrated in Figs. 9 and 10, it is apparent that the fiow of gas andair through the furnace will then be from right to left, as also shownin Fig. 1. During the operation of the furnace with the hood structuresin this position, it is possible for the operator to closely control.Ithe amount of gas admitted to the furnace by operating the forward andreverse pushbuttons as described above, un til the required kdegree ofheat is obtained.

When it is desired to reverse the direction of gas and air through thefurnace, it is only necessary for the operator to depress the topbridging member 74 and hold it kdown untilthe lam 79y lights, whereuponit may be released. he motor 26 will then turnthe shaft 35 untilit hascompleted one half a revolution, whereupon it will be automaticallystopped. Just before the shaft 35 has completed one half a revolution,or in other words, just after the fiange portions 18 have completed thewater seals for the new positions of the hoods 15 and 16, the motor ofthe left hand hood structure will be automatically started by theengagement of the contact 51 with the projection 53. The left hand hoodstructure is then moved from the position shown in Fig. 10 to a positioncorresponding to that occupied by the structure in Fig. 9, whereupon theflow of gas and air from the furnace will be from left to right, theright hand hood structure rthen occupying a position corresponding tothat occupied by the structure in Fig. 10. In this way theentirevmovement of the hood structures necessary for completelyreversing the flow of air and gas through the furnace is automaticallycarried out following the single act on the part of the operator indepressing the top push button.

Obviously, the above described automatic operation of the two hoodstructures is most efficient from the standpoint of fuel consuniption,owing to the fact that no fresh gas is admitted to the furnace followingthe shutting off of gas in the right hand flue 9 until the right handhood structure has almost completed its movement and is adapted todirect the discharge of the productsof combustion into the stack flue 8.In other words, during this movement there is time for the gas remainingin the furnace to be consumed and fresh gas is not admitted to thefurnace and gas regenerator by the opening of left hand flue 9 until thecombustion of the old gas is complete. Obviously this result could notbe obtained if the operation of the left hand hood strucvture wereentirely dependent upon the judgment of the operator, as he would belikely to start the movement of the left hand hood structure to admitfresh gas before the gas remaining in the furnace was completelyconsumed. It is also obvious that the operation of both hood structuresis at all times under the control of the operator, so that the movementthereof can be interrupted whenever desired by merely depressing eitherone of the lower push buttons which are adapted to interrupt the circuitof the closing coils of the starting switches.

In addition to the above described means for automatically controllingthe operation of the hood structures, l have provided additional meanswhereby either hood structure may be caused to come to rest at someintermediate point in its travel from one extreme position to the other,So e that the cover 38 will be swung only part way open instead of allthe way open. Under certain conditions, this position of the hoodstructure mayv be desirable, so as to obtain a partial throttling oi thegas supply to the furnace. is previously described with reiference toyFigs. 6 and 7, the contact lingers 46 and -l'T are mounted on themovable arm ALS, and it is obvious from an inspection of Fig. tl, thatthe fingers i6 and 47 can be caused to register ivith the notch ad intue drum -l before the motor shaiit has completed one halt oi arevolution b v merely advancing the arni S. This has the eiiect ofchecking the right hand movement oi the hood structure before the cover3S is raised to the position oi Fig. An operating rod S8 is connected tothe arm 4S, so that the position ot the arm 48 can be controlled fromthe operating i'loor along With the vpush buttons, it desired. ln thisWay a very close adjustment of the gas supply can be obtained.

`While I have shown my invention as applied to a particular arrangementot reversing apparatus as disclosed in my above mentioned copendingapplication, it is not so limited, but may as ivell be applied to otherIreversing apparatus operating on the saine general principles. I desiretherefore that only such limitations be imposed thereon as come Withinthe scope of the appended claims.

I claim,

l. The combination with 'cooperating duplicate reversing` devices for aregenerative furnace, of electrical controlling mechanism therefor,operable selectively to procure t-he reversing movements of' saiddevices in tin'\d relation or to procure the independent movement ofeither of them.

2. The combination with cooperating duplicate reversing devices for aregenerative turnace, ot' electrical controlling mechanism thereforoperable when desired to vary the iioviv ot gaseous iuel through eitheroi said devices.

3. The combination with cooperating duplicate reversing devices `tor aregenerative furnace, of electrical controlling mechanism thereforoperable selectivelyY toV 'procure the reversing movements oi saiddevices in Atimed relation or to vary the iloiv of gaseous `fuel througheither of them.

;l. rl`he combination with cooperating duplicate reversing' devices ttora regenerative furnace, of electrical controlling mechanism thereforoperable when desired to vary the tioiv ot' gaseous fuel through eitherot' said devices by limited movement thereof 'troni the normal'full-open gas supply position ot such device.

The combination with cooperating duplicate re'versingdevices for aregenerative furnace, oi electrical controlling mechanism lthereforoperable when desired to vary the lovv of gaseous fuel through either'of said devices by bringing such device to rest, iu the act ofreversal, at an intermediate point in its traverse.

(5. The combination with cooperating duplicate reversing devices tor aregenerative furnace, of electrical controlling mechanisni therefor,comprising means tor automatically procuring the reversing movements ofsaid devices in timed relation, and means igor selectively procuringthe. stoppage ot one of said devices, in the act ot reversal, at anintermediate point in its traverse.

T. yihe combination With cooperating duplicate reversing devices for aregenerative Yfurnace, of electrical controlling mechanism therefor,comprising means l'lor automatically procuring the reversing movementsot said devices in timed relation, and means tor manually controllingthe extent ot traverse of one of said devices in its movement towardfuel-supplying position.

8. The combination with cooperating duplicate reversing devices lor aregenerative furnace, ot electrical controlling mechanism thereior,coniprising an actuating motor lor each of said devices, means torautomatically procuring the operation of said motors in timedrelation,and means it'or independently discontinuing the operation ot one oi saidmotors, during the act of rcvers-al.

f). The combination with cooperating duplicate reversing devices for aregenerative furnace, oi' electrical controlling mechanism thereior,comprising an actuating motor for each ot said devices, means forautomatically procuring the operation oiE said motors in' timedrelation, and means for selectively procuring the operation oit one otsaid motors, tera limited duration, to vary the volume of gaseous fueliloiv 'through `its associated device.

l0. The combination with cooperating duplicatel reversing devices lor aregenerative furnace, ot an electric motor tor moving each of saiddevices, a control device :For each motor, means for coordinating theoperations of said control devices, for the actuation or' said reversingdevices in timed relation, and means for manuallypiocuring theindependent operation ot' 'said control devices, ivhenever desired.

ll. In apparatus of the class described, the combination with a set offurnace tlucs, a cover 'for one of said tiues. a movable reversingdevice operative with respectto said fines and adapted by its movementin one direction to 'close said cover, an electric motor, forldrivi'iugf said 'reversin device and a source ot electrical energy, olmeans for connecting said motor to said source for driving saidreversing device in one direction of movement, and a control deviceoperable in timed relation with said reversing device for permittingreversal v of the said motor during a limited portion ot' the movementof said reversing device by said motor to vary the degree of closing ofsaid cover. Y

12. In apparatus of the class described, the combination with a set offurnace i'lnes, a cover for one of said flues, a movable reversingdevice operative with respect to said 'fines and adapted by its movementin one direction to open said cover, an electric motor for driving saidreversing device and a source ot' electrical energy, of means forconnecting` said motor to said source for driving said reversing device,a control device operable in timed relation With said reversing devicefor automatically disconnecting said motor from said source after saidreversing device has opened said cover a.

predetermined amount, and means for adjustine` the operation oi saidcontrol device to vary the degree oit openingv of said cover.

1S. ln apparatus of the class described, the combination with a pair ofmovable hood structnres,fan electric motor for moving each of said hoodstructures and a device for controlling the operation of each ol saidmotors so as to canse a motor to move its hood structure a predeterminedamount,

GEORGE H. ISLEY.

